Revenue leakage is a telecommunications term that pertains to a condition that occurs when a carrier or provider cannot bill for call. Leakage can occur due to misconfigured B-party numbers, faulty switches and routes, or fraudulent or misconfigured interconnect operator switches. Another source of revenue leakage issues is manipulation of Answer No Charge indicators in the SS7 data stream which result in no billable call detail record from being generated.
Other sources of network issues are “pinging” and “Calling Line Identity (CLI) dumping.” Both cause tremendous congestion issues on the network which result in quality of service issues and loss of revenue from legitimate usage. In pinging, an autodialer will make tens of thousands to hundreds of thousands of calls to random B-party numbers and release the line before the call can be answered in the terminating end. CLI dumping is similar, but it occurs in the mobile environment where the CLI is delivered to the terminating phone in hopes that it will elicit a call-back. Related to pinging and CLI dumping is “mechanical dialing.”
Congestion is a major issue for telecommunication networks, either due to deliberate attack or major world events that cause unexpected volumes on the network which cause re-routing of calls and eventual failure. In addition to detecting congestion, to prevent leakage a carrier would have to identify the source of the congestion.
A condition known as “tromboning” is a major source of both revenue leakage and also of network congestion and reduced availability. This activity involves multiple hops across the interconnect either due to fraudulent manipulation of the routing tables for through network manipulation. These extra hops take up bandwidth for legitimate calls and produce revenue for interconnect operators that take advantage of arbitrage of interconnect fees. If a call hops across the interconnect 1000 times, that means that one billable call takes up the bandwidth for 999 other calls in addition to the original call. This results in a loss of bandwidth for the operators and consequently quality of service and revenue issues.
Another source of congestion and failure particularly in an intelligent network (IN), are voting scenarios. Since the IN is critical to the health of a network, voting events will have their voting numbers directly input in the routing tables of the network. Fraudsters have determined that, given the large volume of these votings, some percentage of calls will be misdialed and they therefore purchase these nearby numbers for premium rate services. When misdials occur the fraudster may play back a busy signal prompting the caller to re-dial the misdialed number repeatedly causing huge volumes on the IN network leading to failure of the IN and of critical functions in the network such as 911 service and toll-free services.